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CASIA2 is a non-contact, high-resolution tomographic and biomicroscopic device intended for the in vivo imaging and measurement of ocular structures in the anterior segment. CASIA2 measures corneal thickness, anterior chamber depth and lens thickness.

The Tomey Cornea/Anterior Segment OCT CASIA2 (CASIA2) is a non-contact, high resolution tomographic and biomicroscopic device indicated for in vivo imaging of ocular structures in the anterior segment. The Tomey Cornea/Anterior Segment OCT CASIA2 is indicated as an aid in the visualization and measurement of anterior segment findings. CASIA2 measures corneal thickness, anterior chamber depth and lens thickness.

This medical device product has functions subject to FDA premarket review (corneal thickness, curvature, anterior chamber depth and lens thickness) as well as functions that are not subject to FDA premarket review. For this application, for the (510(k) exempt functions that are not subject to FDA premarket review, FDA assessed those functions only to the extent that they either could adversely impact the safety and effectiveness of the overall device.

CASIA2 consists of several components: the main unit, AC input power source, a touch panel LCD monitor, an external hard drive (HDD), a mouse and a keyboard.

Here’s a breakdown of the acceptance criteria and the study proving the device meets them, based on the provided FDA 510(k) clearance letter for the Tomey CASIA2.

Device: Tomey Cornea/Anterior Segment OCT (CASIA2)
Measurements evaluated: Central Corneal Thickness (CCT), Anterior Chamber Depth (ACD), and Lens Thickness (LT).

1. Table of Acceptance Criteria and Reported Device Performance

The document does not explicitly state pre-defined quantitative acceptance criteria (e.g., "CCT agreement must be within X µm"). Instead, it focuses on demonstrating agreement and precision compared to a legally marketed reference device (LENSTAR LS900). The "acceptance criteria" can be inferred from the study's objective to show substantial equivalence through these performance metrics. The reported device performance is presented as the actual agreement (mean difference and 95% Limits of Agreement - LOA) and precision (Repeatability and Reproducibility %CV).

Therefore, the table below reflects the demonstrated performance and implicitly what was considered acceptable for substantial equivalence.

Note on "Acceptance Criteria": The document implies that meeting or exceeding the performance of the LS900 in terms of precision, and demonstrating good agreement via Bland-Altman analysis, constituted the acceptance for substantial equivalence.

2. Sample Size Used for the Test Set and Data Provenance

• Sample Size for Test Set: A total of 224 subjects were enrolled and completed the study for precision and agreement testing.
  • 55 subjects in the normal group
  • 60 subjects in the cataract group
  • 109 subjects in the special eyes group (eyes without a natural lens or eyes containing artificial materials)
    N for specific analyses (e.g., Agreement Analysis for LT) varied based on acceptable scans (e.g., N=122 for LT agreement, N=138 for CCT/ACD precision, N=76 for LT precision).
• Data Provenance: The document does not explicitly state the country of origin. It indicates "The subjects of this study had no notable or unexpected/untoward assessments..." which suggests a single clinical site. However, no specific country is mentioned.
• Retrospective or Prospective: The study was a prospective clinical study, as subjects were "enrolled," "randomized," and "assigned" to configurations and sequences, and data was collected during the study.

3. Number of Experts Used to Establish Ground Truth for the Test Set and Qualifications

• The document implies that the LENSTAR LS900 device itself served as the reference standard for establishing "ground truth" (or more accurately, the comparator for agreement) for the measured parameters.
• It states that "The clinical site had 3 device operators trained on the devices used in the study."
• Qualifications of Experts: The specific qualifications (e.g., radiologist, ophthalmologist, optometrist expertise, years of experience) of these 3 device operators are not explicitly stated in the provided text.

4. Adjudication Method for the Test Set

• The document states, "Additional scans were taken at the operator's discretion if image quality was unacceptable based on the device DFU and the Tomey CASIA2 Reference Guide and included, missing scans, truncated scans, image defocus, floaters, presence of eye blinks, eye motion, etc. Each device operator had up to 3 attempts to obtain an acceptable scan for each of the required scans."
• This suggests an operational approach to ensure data quality rather than a formal, independent adjudication process (e.g., 2+1/3+1 consensus by experts) for the measurements themselves. The "ground truth" was derived from the in-device measurements of the LS900, not a separate expert review. Therefore, there was no expert consensus-based adjudication method for the measurements.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

• No, a traditional MRMC comparative effectiveness study was not done.
• The study design was focused on device-to-device agreement and precision (CASIA2 vs. LENSTAR LS900) rather than evaluating how human readers' performance (e.g., diagnostic accuracy) improved with or without AI assistance.
• The CASIA2 is described as a "tomographic and biomicroscopic device intended for the in vivo imaging and measurement of ocular structures," with software providing "quantitative outputs." It does not appear to be an AI-assisted diagnostic aid for image interpretation that would typically require an MRMC study to show human reader benefit.

6. Standalone (Algorithm Only Without Human-in-the-Loop Performance)

• The study primarily assessed the measurement performance of the CASIA2 device (algorithm/system) in generating quantitative outputs (CCT, ACD, LT) and compared these directly with a reference device. It's implied that these measurements are generated automatically by the device's software.
• The role of the human operators was to acquire an "acceptable scan" based on predefined image quality criteria, not to interpret the images or provide a human "answer" for comparison with an AI-generated reading.
• Therefore, the precision and agreement studies essentially represent the standalone performance of the CASIA2's measurement capabilities compared to the LS900.

7. Type of Ground Truth Used

• The "ground truth" (or clinical reference standard) for comparison was the measurements obtained from the legally marketed predicate/reference device, LENSTAR LS900.
• This is a device-based comparative ground truth, not expert consensus, pathology, or outcomes data. The study aimed to show that the CASIA2's measurements were interchangeable or highly agreeable with those from an established, cleared device.

8. Sample Size for the Training Set

• The document describes a clinical study for validation/testing of the updated software. It does not provide any information about a separate training set size for the development of the algorithms generating these quantitative measurements.
• It only mentions: "The device is a software upgraded version of the predicate K213265 that provides quantitative measurements. All quantitative measurements are derived from OCT images acquired with optical coherence tomography." This implies the software update incorporated algorithms to derive these measurements, but details on their development (including training data) are not provided in this 510(k) summary.

9. How the Ground Truth for the Training Set Was Established

• As the document does not describe the training set or its development, there is no information provided on how the ground truth for any training set was established.

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The Tomey Corneal Anterior Segment OCT CASIA2 is a non-contact, high resolution tomographic and biomicrosopic device indicated for the in vivo imaging of ocular structures in the anterior segment. The Tomey Corneal Anterior Segment OCT CASIA2 is indicated as an aid in the visualization of anterior segment findings.

The Tomey Cornea/Anterior Segment OCT CASIA2 (CASIA2) is a non-contact, high resolution tomographic and biomicrocopic device indicated for in vivo imaging of ocular structures in the anterior segment. The Tomey Cornea/Anterior Segment OCT CASIA2 is indicated as an aid in the visualization of anterior segment findings. CASIA2 consists of several components: the main unit, AC input power source, a touch panel LCD monitor, an external hard drive (HDD), a mouse and a keyboard. CASIA2 is an anterior segment OCT that obtains images by A-scanning with swept-source OCT. OCT images are created by the intensity of the light (backscattered light) that returns in the same path as that of incident light among the scattered light of each tissue. Thus, it is created with higher intensity in the tissues that generate strong backward scattering.

Here's a breakdown of the acceptance criteria and the study proving the device meets them, based on the provided text:

Acceptance Criteria and Device Performance

The provided text doesn't explicitly list "acceptance criteria" in a table format with numerical targets. Instead, it describes a comparative clinical study where the Tomey Cornea/Anterior Segment OCT CASIA2 was compared against a predicate device (Optovue RTVue XR OCT Avanti) for image quality and visualization of anatomical structures and pathologies. The "acceptance criteria" are implicitly demonstrated by showing that the CASIA2 performs at least as well as and in many cases better than the predicate device for its intended use of visualizing anterior segment findings.

The following table summarizes the reported device performance and the implicitly met acceptance criteria of being comparable or superior to the predicate device.

Study Proving Device Meets Acceptance Criteria

2. Sample Size and Data Provenance:

• Test Set Sample Size: 134 subjects.
  • 45 Normal subjects
  • 46 Cataract subjects
  • 43 Glaucoma subjects
• Data Provenance: The text states it was a "prospective comparative clinical performance study." While the specific country of origin isn't stated for the clinical data, Tomey Corporation is based in Japan (as per the submitter information), and the consultant ORA, Inc. is in the USA. Clinical studies for FDA submissions typically involve diverse populations or are clearly described if conducted solely in one region. However, the text only specifies "subjects."

3. Number of Experts and Qualifications:

• Number of Experts: 3 masked graders.
• Qualifications of Experts: Not explicitly stated beyond "masked graders." It is highly probable, given the nature of the study, that these graders were ophthalmologists or optometrists with expertise in interpreting OCT images of the anterior segment. The term "masked graders" implies they were blinded to key study parameters (subject, disease population, device, and results from other graders).

4. Adjudication Method for the Test Set:

• The image grading procedure was "pre-specified in the study protocol."
• Images were assessed by 3 masked graders.
• The results report "grader average score" and "individual grader comparisons." This indicates that the individual scores of the three graders were analyzed, and a pooled average was used for comparison. There is no explicit mention of an "adjudication" process in the sense of a definitive consensus or tie-breaking mechanism if graders disagreed. The reporting suggests independent grading followed by aggregation or direct comparison of individual scores.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study:

• Was it done? Yes, a multi-reader, multi-case comparative study was conducted, as 3 masked graders evaluated images from 134 subjects across different disease states and scan types.
• Effect Size (Human Readers Improvement with AI vs. No AI): This study does not involve AI assistance for human readers. It is a comparison of two different OCT devices (Tomey CASIA2 vs. Optovue Avanti) for image quality as assessed by human readers. Therefore, there is no effect size related to human reader improvement with AI assistance. The study implicitly shows that the CASIA2 enables human readers to observe pathology and anatomical structures better or as often as the predicate device due to its image quality.

6. Standalone (Algorithm Only) Performance:

• The text describes the device as providing "imaging of ocular structures" and being "an aid in the visualization of anterior segment findings." The performance evaluation focuses on the quality of these images as assessed by human graders. There is no mention of an embedded algorithm providing automated diagnoses or measurements that would require a standalone performance study. The device itself is the imaging system, not an AI diagnostic algorithm.

7. Type of Ground Truth Used:

• The ground truth for the assessment of image quality, visibility of structures, and pathology was expert perception/consensus through grading by 3 masked experts. The study directly compared the ability of the new device's images versus the predicate device's images to allow observation by these experts. Patients were categorized by clinical diagnosis (normal, cataract, glaucoma), implying these clinical diagnoses served as the underlying "truth" for evaluating the device's utility in those populations, though the primary outcome was image quality.

8. Sample Size for the Training Set:

• The document does not provide information regarding a training set sample size. This is expected as the Tomey CASIA2 is an imaging device, not an AI algorithm that requires a dedicated training set to learn patterns. The study focuses on the performance of the device's output (images) rather than the performance of a learned model.

9. How Ground Truth for Training Set was Established:

• Since there's no mention of an AI algorithm requiring a training set, this information is not applicable and not provided in the document.

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